scholarly journals Precipitation thresholds and drought-induced tree die-off: insights from patterns ofPinus edulismortality along an environmental stress gradient

2013 ◽  
Vol 200 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Michael J. Clifford ◽  
Patrick D. Royer ◽  
Neil S. Cobb ◽  
David D. Breshears ◽  
Paulette L. Ford
Keyword(s):  
Environmental Stress ◽  
Stress Gradient ◽  
Precipitation Thresholds

Indirect effects and facilitation among native and non-native species promote invasion success along an environmental stress gradient

2013 ◽  
Vol 101 (4) ◽  
pp. 905-915 ◽  
Author(s):  
Phoebe L. Zarnetske ◽  
Tarik C. Gouhier ◽  
Sally D. Hacker ◽  
Eric W. Seabloom ◽  
Vrushali A. Bokil
Keyword(s):  
Environmental Stress ◽  
Indirect Effects ◽  
Native Species ◽  
Stress Gradient ◽  
Invasion Success

Patterns of plant invasion along an environmental stress gradient

2006 ◽  
Vol 17 (1) ◽  
pp. 47-56 ◽  
Author(s):  
A.S. MacDougall ◽  
J. Boucher ◽  
R. Turkington ◽  
G.E. Bradfield
Keyword(s):  
Environmental Stress ◽  
Plant Invasion ◽  
Stress Gradient

scholarly journals Consumer mobility predicts impacts of herbivory across an environmental stress gradient

Ecology ◽  
2019 ◽  
Vol 101 (1) ◽  
Author(s):  
Robert W. Lamb ◽  
Franz Smith ◽  
Jon D. Witman
Keyword(s):  
Environmental Stress ◽  
Stress Gradient

Inducible versus constitutive antioxidant defenses in algae along an environmental stress gradient

2020 ◽  
Vol 640 ◽  
pp. 107-115
Author(s):  
KL Van Alstyne ◽  
L Sutton ◽  
SA Gifford
Keyword(s):  
Environmental Stress ◽  
Stress Gradient ◽  
Marine Macroalgae ◽  
Antioxidant Defenses ◽  
Inducible Defenses ◽  
Signaling Mechanism ◽  
Oxidative Stresses ◽  
Intertidal Species ◽  
Ulva Fenestrata ◽  
Antiherbivore Defenses

Optimal defense theory (ODT) predicts that antiherbivore defenses should be constitutive when plants are frequently attacked and inducible when the probability of attack is low. Like antiherbivore defenses, antioxidant defenses can be inducible or constitutive. We hypothesized the ODT predictions should apply to antioxidant defenses; thus, species inhabiting environments where oxidative stresses occur frequently should produce constitutive antioxidant defenses, whereas species in environments where stresses occur less frequently should produce inducible defenses. We tested this hypothesis by attempting to induce production of the antioxidant precursor dimethylsulfoniopropionate (DMSP) in 4 ulvoid algae species that experience different levels of environmental stress because they are zoned along a tidal gradient. The 2 lower intertidal species Ulvaria obscura and Ulva fenestrata, which experience oxidative stresses less frequently, induced DMSP production in response to applications of the chemical oxidant hydrogen peroxide within 7 d, whereas the higher intertidal species Ulva linza and Ulva intestinalis, which regularly experience oxidative stress, did not have increased DMSP concentrations. This study demonstrates a novel waterborne signaling mechanism for DMSP induction in marine macroalgae and provides evidence of selection for inducible antioxidant defenses in organisms experiencing less frequent environmental stresses.

Woodland recovery following drought-induced tree mortality across an environmental stress gradient

2015 ◽  
Vol 21 (10) ◽  
pp. 3685-3695 ◽  
Author(s):  
Miranda D. Redmond ◽  
Neil S. Cobb ◽  
Michael J. Clifford ◽  
Nichole N. Barger
Keyword(s):  
Environmental Stress ◽  
Tree Mortality ◽  
Stress Gradient

PHYSIOLOGY OF THE ROCKY INTERTIDAL PREDATORNUCELLA OSTRINAALONG AN ENVIRONMENTAL STRESS GRADIENT

Ecology ◽  
2001 ◽  
Vol 82 (10) ◽  
pp. 2816-2829 ◽  
Author(s):  
Elizabeth P. Dahlhoff ◽  
Bradley A. Buckley ◽  
Bruce A. Menge
Keyword(s):  
Environmental Stress ◽  
Stress Gradient ◽  
Rocky Intertidal

scholarly journals Functional diversity of habitat formers declines scale-dependently across an environmental stress gradient

Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 135-149
Author(s):  
Laura Cappelatti ◽  
Alizée R. L. Mauffrey ◽  
John N. Griffin
Keyword(s):  
Environmental Stress ◽  
Functional Diversity ◽  
Stress Gradient ◽  
High Stress ◽  
Small Scale ◽  
Marine Habitat ◽  
Functional Richness ◽  
Expected Values ◽  
Functional Dispersion ◽  
Habitat Formers

Abstract Marine habitat formers such as seaweeds and corals are lynchpins of coastal ecosystems, but their functional diversity and how it varies with scale and context remains poorly studied. Here, we investigate the functional diversity of seaweed assemblages across the rocky intertidal stress gradient at large (zones) and small (quadrat) scales. We quantified complementary metrics of emergent group richness, functional richness (functional space occupied) and functional dispersion (trait complementarity of dominant species). With increasing shore height, under species loss and turnover, responses of functional diversity were scale- and metric-dependent. At the large scale, functional richness contracted while—notwithstanding a decline in redundancy—emergent group richness and functional dispersion were both invariant. At the small scale, all measures declined, with the strongest responses evident for functional and emergent group richness. Comparisons of observed versus expected values based on null models revealed that functional richness and dispersion were greater than expected in the low shore but converged with expected values higher on the shore. These results show that functional diversity of assemblages of marine habitat formers can be especially responsive to environmental stress gradients at small scales and for richness measures. Furthermore, niche-based processes at the small—neighbourhood—scale can favour co-occurrence of functionally distinctive species under low, but not high, stress, magnifying differences in functional diversity across environmental gradients. As assemblages of marine habitat formers face accelerating environmental change, further studies examining multiple aspects of functional diversity are needed to elucidate patterns, processes, and ecosystem consequences of community (dis-)assembly across diverse groups.

scholarly journals Unsustainable Land Use, Sediment-Laden Runoff, and Chronic Raw Sewage Offset the Benefits of Coral Reef Ecosystems in a No-Take Marine Protected Area

2017 ◽  
Vol 6 (2) ◽  
pp. 292 ◽  
Author(s):  
Edwin A Hernandez-Delgado ◽  
Jeiger L. Medina-Muniz ◽  
Hernando Mattei ◽  
Jose Norat-Ramirez
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Community Structure ◽  
Coral Reefs ◽  
Environmental Stress ◽  
Watershed Management ◽  
Stress Gradient ◽  
Sewage Pollution ◽  
Benthic Community Structure ◽  
Benthic Assemblages

Unsustainable land uses may result in poor watershed management, increased soil erosion, poorly-planned urban development, increased runoff, and sewage pollution, creating an environmental stress gradient across coastal coral reefs. This study was aimed at: 1) Evaluating water quality within and outside the Canal Luis Peña Natural Reserve (CLPNR), Culebra Island, Puerto Rico; 2) Determining if there was any significant environmental stress gradient associated to land-based non-point source pollution; and 3) Characterizing shallow-water coral reef communities across the gradient. Strong gradient impacts associated to sediment-laden and nutrient-loaded runoff pulses, in combination with non-point raw sewage pulses, and sediment bedload, impacted coastal coral reefs. Water quality showed significant spatio-temporal fluctuations (p<0.0001), largely responding to heavy rainfall and subsequent runoff pulses. Benthic community structure showed significant spatial variation along the environmental stress gradient (p=0.0002). Macroalgae, dead coral surfaces, algal turf, and low coral species richness, species diversity index (H’c), and evenness (J’c) dominated benthic assemblages across reefs frequently impacted by runoff pulses and sediment bedload. The combination of fecal coliform and enterococci concentrations were correlated with variation in benthic community structure (Rho=0.668; p=0.0020). The combined variation in salinity, dissolved oxygen and enterococci concentrations explained 75% of the observed spatial variation in benthic assemblages (R2=0.7461; p=0.0400). Local human stressors affected coral reefs within no-take CLPNR and risk analyses suggest it may offset its ecological benefits. There is a need to design and implement integrated coastal-watershed management strategies to address multiple land use activities, including erosion-control best management practices, watershed reforestation, and sewage pollution control.

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